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<H1 class="no-header">user_caps 5 2024-06-08 ncurses 6.5 File formats</H1>
<PRE>
<STRONG><A HREF="user_caps.5.html">user_caps(5)</A></STRONG>                     File formats                     <STRONG><A HREF="user_caps.5.html">user_caps(5)</A></STRONG>




</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       user_caps - user-defined <EM>terminfo</EM> capability format


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>infocmp</STRONG> <STRONG>-x</STRONG>

       <STRONG>tic</STRONG> <STRONG>-x</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>

</PRE><H3><a name="h3-Background">Background</a></H3><PRE>
       Before  <EM>ncurses</EM>  5.0,  terminfo  databases  used  a <EM>fixed</EM> <EM>repertoire</EM> of
       terminal capabilities designed for the SVr2 terminal database in  1984,
       and  extended in stages through SVr4 (1989), and standardized in X/Open
       Curses starting in 1995.

       Most of the <EM>extensions</EM> in this fixed repertoire were additions  to  the
       tables of Boolean, numeric and string capabilities.  Rather than change
       the meaning of an existing capability,  a  new  name  was  added.   The
       terminfo  database  uses  a  binary  format;  binary  compatibility was
       ensured by using a header which gave the number of items in the  tables
       for each type of capability.  The standardization was incomplete:

       <STRONG>o</STRONG>   The  <EM>binary</EM>  <EM>format</EM>  itself  is  not described in the X/Open Curses
           documentation.  Only the <EM>source</EM> <EM>format</EM> is described.

           Library developers rely upon the SVr4 documentation,  and  reverse-
           engineering the compiled terminfo files to match the binary format.

       <STRONG>o</STRONG>   Lacking a standard for the binary format, most implementations copy
           the SVr2 binary format, which uses 16-bit signed integers,  and  is
           limited to 4096-byte entries.

           The  format  cannot  represent very large numeric capabilities, nor
           can it represent large numbers of special keyboard definitions.

       <STRONG>o</STRONG>   The tables of capability names differ between implementations.

           Although they <EM>may</EM> provide all of the standard capability names, the
           position  in the tables differs because some features were added as
           needed, while others were added  (out  of  order)  to  comply  with
           X/Open Curses.

           While  <EM>ncurses</EM>' repertoire of predefined capabilities is closest to
           Solaris, Solaris's terminfo database has a few differences from the
           list  published  by  X/Open  Curses.   For  example, <EM>ncurses</EM> can be
           configured with tables which match the terminal databases for  AIX,
           HP-UX or OSF/1, rather than the default Solaris-like configuration.

       <STRONG>o</STRONG>   In  SVr4  curses  and  <EM>ncurses</EM>, the terminal database is defined at
           compile-time using a text file which lists the  different  terminal
           capabilities.

           In  principle,  the  text-file  can  be  extended,  but  doing this
           requires recompiling and reinstalling the library.   The  text-file
           used  in  <EM>ncurses</EM>  for  terminal  capabilities includes details for
           various systems past the documented X/Open  Curses  features.   For
           example, <EM>ncurses</EM> supports these capabilities in each configuration:

               memory_lock
                    (meml) lock memory above cursor

               memory_unlock
                    (memu) unlock memory

               box_chars_1
                    (box1) box characters primary set

           The memory lock/unlock capabilities were included because they were
           used in the X11R6 terminal  description  for  <STRONG>xterm(1)</STRONG>.   The  <EM>box1</EM>
           capability  is  used  in  tic  to  help  with terminal descriptions
           written for AIX.

       During the 1990s, some users were reluctant to use terminfo in spite of
       its performance advantages over termcap:

       <STRONG>o</STRONG>   The  fixed  repertoire  prevented  users  from  adding features for
           unanticipated terminal improvements  (or  required  them  to  reuse
           existing capabilities as a workaround).

       <STRONG>o</STRONG>   The  limitation  to  16-bit  signed  integers  was  also mentioned.
           Because termcap stores everything as a string, it  could  represent
           larger numbers.

       Although  termcap's  extensibility  was  rarely  used (it was never the
       <EM>speaker</EM> who had actually used the feature), the criticism had a  point.
       <EM>ncurses</EM>   5.0  provided  a  way  to  detect  nonstandard  capabilities,
       determine their type and optionally store and retrieve them  in  a  way
       which did not interfere with other applications.  These are referred to
       as <EM>user-defined</EM> <EM>capabilities</EM> because no modifications to the  toolset's
       predefined capability names are needed.

       The  <EM>ncurses</EM>  utilities <STRONG>tic</STRONG> and <STRONG>infocmp</STRONG> have a command-line option "-x"
       to  control  whether  the  nonstandard  capabilities  are   stored   or
       retrieved.   A  library function <STRONG>use_extended_names</STRONG> is provided for the
       same purpose.

       When compiling a terminal database, if "-x" is set, <STRONG>tic</STRONG>  will  store  a
       user-defined  capability  if  the  capability  name  is  not one of the
       predefined names.

       Because <EM>ncurses</EM> provides  a  termcap  library  interface,  these  user-
       defined capabilities may be visible to termcap applications:

       <STRONG>o</STRONG>   The   termcap  interface  (like  all  implementations  of  termcap)
           requires that the capability names are 2-characters.

           When  the  capability  is  simple  enough  for  use  in  a  termcap
           application, it is provided as a 2-character name.

       <STRONG>o</STRONG>   There  are  other user-defined capabilities which refer to features
           not usable in termcap, e.g., parameterized strings  that  use  more
           than two parameters or use more than the trivial expression support
           provided by termcap.  For these, the terminfo database should  have
           only capability names with 3 or more characters.

       <STRONG>o</STRONG>   Some terminals can send distinct strings for special keys (cursor-,
           keypad-  or  function-keys)  depending  on  modifier  keys  (shift,
           control,  etc.).   While  terminfo  and  termcap  have  a set of 60
           predefined function-key names, to which a series  of  keys  can  be
           assigned,   that  is  insufficient  for  more  than  a  dozen  keys
           multiplied by more than a couple  of  modifier  combinations.   The
           <EM>ncurses</EM>  database  uses  a  convention based on <STRONG>xterm(1)</STRONG> to provide
           extended special-key names.

           Fitting that into termcap's limitation of 2-character  names  would
           be   pointless.   These  extended  keys  are  available  only  with
           terminfo.


</PRE><H3><a name="h3-Recognized-Capabilities">Recognized Capabilities</a></H3><PRE>
       The <EM>ncurses</EM> library uses the user-definable  capabilities.   While  the
       terminfo  database  may  have  other extensions, <EM>ncurses</EM> makes explicit
       checks for these:

          AX <EM>Boolean</EM>, asserts that the terminal interprets SGR 39 and  SGR  49
             by  resetting  the foreground and background color, respectively,
             to the default.

             This is a feature recognized by the <STRONG>screen</STRONG> program as well.

          E3 <EM>string</EM>, tells how to  clear  the  terminal's  scrollback  buffer.
             When present, the <STRONG><A HREF="clear.1.html">clear(1)</A></STRONG> program sends this before clearing the
             terminal.

             The command "<STRONG>tput</STRONG> <STRONG>clear</STRONG>" does the same thing.

          NQ <EM>Boolean</EM>, used to suppress a consistency  check  in  tic  for  the
             <EM>ncurses</EM>  capabilities  in user6 through user9 (u6, u7, u8 and u9)
             which tell how to query the terminal's cursor  position  and  its
             device attributes.

          RGB
             <EM>Boolean</EM>,   <EM>number</EM>   <STRONG>or</STRONG>   <EM>string</EM>,   used   to   assert   that  the
             <STRONG>set_a_foreground</STRONG> and <STRONG>set_a_background</STRONG> capabilities correspond  to
             <EM>direct</EM>  <EM>colors</EM>,  using  an RGB (red/green/blue) convention.  This
             capability  allows   the   <STRONG>color_content</STRONG>   function   to   return
             appropriate   values   without   requiring   the  application  to
             initialize colors using <STRONG>init_color</STRONG>.

             The capability type determines the values which <EM>ncurses</EM> sees:

             <EM>Boolean</EM>
                implies that the number of bits for red, green  and  blue  are
                the  same.   Using  the maximum number of colors, <EM>ncurses</EM> adds
                two, divides that sum by three, and assigns the result to red,
                green and blue in that order.

                If the number of bits needed for the number of colors is not a
                multiple of three, the blue (and  green)  components  lose  in
                comparison to red.

             <EM>number</EM>
                tells  <EM>ncurses</EM>  what result to add to red, green and blue.  If
                <EM>ncurses</EM> runs out of bits, blue (and green) lose just as in the
                <EM>Boolean</EM> case.

             <EM>string</EM>
                explicitly  list  the  number  of bits used for red, green and
                blue components as a slash-separated list of decimal integers.

             Because there are several  RGB  encodings  in  use,  applications
             which  make  assumptions  about  the number of bits per color are
             unlikely to work reliably.  As a trivial case, for  example,  one
             could  define  <STRONG>RGB#1</STRONG> to represent the standard eight ANSI colors,
             i.e., one bit per color.

          U8 <EM>number</EM>, asserts that <EM>ncurses</EM> must use Unicode  values  for  line-
             drawing  characters,  and  that  it  should  ignore the alternate
             character set capabilities when the locale uses  UTF-8  encoding.
             For  more  information, see the discussion of <STRONG>NCURSES_NO_UTF8_ACS</STRONG>
             in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>.

             Set this capability to a nonzero value to enable it.

          XM <EM>string</EM>, override <EM>ncurses</EM>'s built-in string which enables/disables
             <STRONG>xterm(1)</STRONG> mouse mode.

             <EM>ncurses</EM>  sends a character sequence to the terminal to initialize
             mouse mode, and when the user clicks the  mouse  buttons  or  (in
             certain  modes) moves the mouse, handles the characters sent back
             by the terminal to tell it what was done with the mouse.

             The mouse protocol  is  enabled  when  the  <EM>mask</EM>  passed  in  the
             <STRONG>mousemask</STRONG>  function  is nonzero.  By default, <EM>ncurses</EM> handles the
             responses for the X11 xterm mouse protocol.  It also knows  about
             the  <EM>SGR</EM>  <EM>1006</EM>  xterm mouse protocol, but must to be told to look
             for this specifically.  It will not be able to guess  which  mode
             is  used,  because  the  responses  are  enough  alike  that only
             confusion would result.

             The <STRONG>XM</STRONG> capability has a single parameter.  If nonzero, the  mouse
             protocol  should  be enabled.  If zero, the mouse protocol should
             be disabled.  <EM>ncurses</EM> inspects this capability if it is  present,
             to  see whether the 1006 protocol is used.  If so, it expects the
             responses to use the <EM>SGR</EM> <EM>1006</EM> xterm mouse protocol.

             The xterm mouse protocol is used  by  other  terminal  emulators.
             The  terminal database uses building-blocks for the various xterm
             mouse  protocols  which  can  be  used  in  customized   terminal
             descriptions.

             The terminal database building blocks for this mouse feature also
             have  an  experimental  capability  <EM>xm</EM>.   The   "xm"   capability
             describes  the mouse response.  Currently there is no interpreter
             which would use  this  information  to  make  the  mouse  support
             completely data-driven.

             <EM>xm</EM> shows the format of the mouse responses.  In this experimental
             capability, the parameters are

               <EM>p1</EM>   y-ordinate

               <EM>p2</EM>   x-ordinate

               <EM>p3</EM>   button

               <EM>p4</EM>   state, e.g., pressed or released

               <EM>p5</EM>   y-ordinate starting region

               <EM>p6</EM>   x-ordinate starting region

               <EM>p7</EM>   y-ordinate ending region

               <EM>p8</EM>   x-ordinate ending region

             Here are  examples  from  the  terminal  database  for  the  most
             commonly used xterm mouse protocols:

               xterm+x11mouse|X11 xterm mouse protocol,
                       kmous=\E[M, XM=\E[?1000%?%p1%{1}%=%th%el%;,
                       xm=\E[M
                          %?%p4%t%p3%e%{3}%;%' '%+%c
                          %p2%'!'%+%c
                          %p1%'!'%+%c,

               xterm+sm+1006|xterm SGR-mouse,
                       kmous=\E[&lt;, XM=\E[?1006;1000%?%p1%{1}%=%th%el%;,
                       xm=\E[&lt;%i%p3%d;
                          %p1%d;
                          %p2%d;
                          %?%p4%tM%em%;,


</PRE><H3><a name="h3-Extended-Key-Definitions">Extended Key Definitions</a></H3><PRE>
       Several  terminals  provide  the  ability  to send distinct strings for
       combinations of modified special keys.  There is no standard  for  what
       those keys can send.

       Since  1999,  <STRONG>xterm(1)</STRONG>  has  supported  <EM>shift</EM>,  <EM>control</EM>,  <EM>alt</EM>, and <EM>meta</EM>
       modifiers which produce distinct special-key strings.   In  a  terminal
       description,  <EM>ncurses</EM>  has  no special knowledge of the modifiers used.
       Applications can use the <EM>naming</EM> <EM>convention</EM>  established  for  <STRONG>xterm</STRONG>  to
       find these special keys in the terminal description.

       Starting  with  the  <EM>curses</EM> convention that capability codes describing
       the input generated by a terminal's key caps begin with "k",  and  that
       shifted  special  keys  use uppercase letters in their names, <EM>ncurses</EM>'s
       terminal database defines the following names  and  codes  to  which  a
       suffix is added.

            <STRONG>Code</STRONG>   <STRONG>Description</STRONG>
            -------------------------------------------------------------------
            <STRONG>kDC</STRONG>    shifted kdch1 (delete character)
            <STRONG>kDN</STRONG>    shifted kcud1 (cursor down)
            <STRONG>kEND</STRONG>   shifted kend (end)
            <STRONG>kHOM</STRONG>   shifted khome (home)
            <STRONG>kLFT</STRONG>   shifted kcub1 (cursor back)
            <STRONG>kNXT</STRONG>   shifted knext (next)
            <STRONG>kPRV</STRONG>   shifted kprev (previous)
            <STRONG>kRIT</STRONG>   shifted kcuf1 (cursor forward)
            <STRONG>kUP</STRONG>    shifted kcuu1 (cursor up)

       Keycap  nomenclature on the Unix systems for which <EM>curses</EM> was developed
       differs from today's ubiquitous descendants of the IBM  PC/AT  keyboard
       layout.  In the foregoing, interpret "backward" as "left", "forward" as
       "right", "next" as "page down", and "prev(ious)" as "page up".

       These are the suffixes used to denote the modifiers:

            <STRONG>Value</STRONG>   <STRONG>Description</STRONG>
            ----------------------------------
            2       Shift
            3       Alt
            4       Shift + Alt
            5       Control
            6       Shift + Control
            7       Alt + Control
            8       Shift + Alt + Control
            9       Meta
            10      Meta + Shift
            11      Meta + Alt
            12      Meta + Alt + Shift
            13      Meta + Ctrl
            14      Meta + Ctrl + Shift
            15      Meta + Ctrl + Alt
            16      Meta + Ctrl + Alt + Shift

       None of these are predefined; terminal descriptions can refer to  <EM>names</EM>
       which <EM>ncurses</EM> will allocate at runtime to <EM>key-codes</EM>.  To use these keys
       in an <EM>ncurses</EM> program, an application could do this:

       <STRONG>o</STRONG>   using a list of extended key  <EM>names</EM>,  ask  <STRONG><A HREF="curs_terminfo.3x.html">tigetstr(3x)</A></STRONG>  for  their
           values, and

       <STRONG>o</STRONG>   given  the  list  of  values,  ask <STRONG><A HREF="key_defined.3x.html">key_defined(3x)</A></STRONG> for the <EM>key-code</EM>
           which would be returned for those keys by <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
       The "-x" extension feature of <STRONG>tic</STRONG>  and  <STRONG>infocmp</STRONG>  has  been  adopted  in
       NetBSD  curses.   That implementation stores user-defined capabilities,
       but makes no use of these capabilities itself.


</PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
       Thomas E. Dickey
       beginning with <EM>ncurses</EM> 5.0 (1999)


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       <STRONG><A HREF="infocmp.1m.html">infocmp(1m)</A></STRONG>, <STRONG><A HREF="tic.1m.html">tic(1m)</A></STRONG>

       The  terminal  database  section  <EM>NCURSES</EM>  <EM>USER-DEFINABLE</EM>  <EM>CAPABILITIES</EM>
       summarizes  commonly-used  user-defined  capabilities which are used in
       the terminal descriptions.  Some of those  features  are  mentioned  in
       <STRONG>screen(1)</STRONG> or <STRONG>tmux(1)</STRONG>.

       <EM>XTerm</EM>  <EM>Control</EM>  <EM>Sequences</EM>  provides further information on the <STRONG>xterm(1)</STRONG>
       features that are used in these extended capabilities.



ncurses 6.5                       2024-06-08                      <STRONG><A HREF="user_caps.5.html">user_caps(5)</A></STRONG>
</PRE>
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<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-Background">Background</a></li>
<li><a href="#h3-Recognized-Capabilities">Recognized Capabilities</a></li>
<li><a href="#h3-Extended-Key-Definitions">Extended Key Definitions</a></li>
</ul>
</li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-AUTHORS">AUTHORS</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
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